Demands on the vehicle's systems are such that many cars now have their alternators plumbed into the engine cooling system, and are even shaft-driven because of belt slippage. 12V has proven to be a significant burden on carmakers wiring-wise these days with all of the demand for electronics in the car. It wasn't too long ago that cars only had 2 or so computers - the engine control unit, and the ABS controller. I've got a car with almost a dozen - engine, climate, "chassis" (lights, locking, wipers, etc), suspension control, ABS/traction control, airbag, navigation...god knows what else. No DVD player or "entertainment" system beyond the stereo.
Electric steering pumps are increasingly common - they're compact, easy to locate anywhere, easy to control which simplifies hydraulics, and help with fuel economy since there's much less parasitic load.
Even back in the 80's, it was a problem. Audi located the battery in the back seat for crash safety, engine compartment room, and battery longevity (less temperature extremes) - but the cable that goes to the front is pretty damn massive, and failures where they splice a Y off to the main fusebox is fairly common and cause lots of problems because of the voltage drop. The problem was exacerbated by the use of an electric cooling fan which could draw well over a thousand watts - I think the fuseable link by the fan motor is rated for over 100A.
Car companies have been making noises about switching to 24V systems, with a 12V bus only for cigarette lighter accessories...it'd cut down significantly on the size of the wiring needed (which means cutting down on weight!) and transmission losses, both of which will improve gas economy.